This invention relates to a component layout for a two cycle engine and more particularly to an improved compact component and induction system for a two cycle internal combustion engine.
Two cycle engines are receiving considerable attention due to their possible application for automotive use. An important advantage of a two cycle engine, particularly for automotive use, is the relatively compact nature of such engines. However, in order to improve the efficiency and exhaust emission control of such engines, it has been proposed to employ a direct fuel injection system for such engines. In some applications, air/fuel injectors are being considered.
As is well know, a two cycle, crankcase compression engine inducts its air charge into the crankcase chambers of the engine where the charge is compressed and then transferred to the combustion chambers. This means that the induction system for a two cycle engine, unlike that of a conventional four cycle engine, is disposed at the lower portion of the engine rather than the upper portion of the engine. When such engines are employed for motor vehicles, certain auxiliaries must be driven off the engine. This is particularly true where the engine is provided with an air/fuel injector inasmuch as it is the practice to drive an air compressor for the air injection portion of the fuel/air injector from the engine. In conjunction with two cycle engines, this can present certain problems in respect to the placement and driving of the various accessories and auxiliaries driven by the engine.
It is, therefore, a principal object to this invention to provide an improved component layout for a two cycle engine.
It is further object to this invention to provide an improved component layout and drive arrangement for a two cycle engine that permits the engine to be employed in conjunction with an automotive type application.
As has been noted, the use of air/fuel injectors for two cycle engines requires the supply of compressed air for the air/fuel injectors. Of course, the air supplied to the air/fuel injectors should be filtered and this necessitate the use of an air filter element and induction system for supplying air to the air compressor. However, in order to improve the efficiency of the air compressor and to permit a small size, it is desirable to reduce the length of the intake system for the air compressor and also to position the air filter close to the air compressor. Of course, the main induction system for the engine also requires an air filter and certain advantages can be employed if the same air filter is employed for filtering both the induction system air and the air supplied to the air compressor. Of course, this gives rise to obvious problems in connection with component layout.
It is, therefore, a further object to this invention to provide an improved air induction system for the intake and air compressor of a two cycle, crankcase compression engine.
It is a further object to this invention to provide an air intake system for an air compressor of an engine and the engine induction system wherein a single air filter element filters the air to both the devices while still maintaining a compact construction and short runner lengths.
As has already been noted, one disadvantage in the use of two cycle engines in automotive applications is the fact that the induction system for the engine is positioned at the lower portion of the engine rather than the upper portion as with a more conventional four stroke engine. Furthermore, the induction system for two cycle engines normally employs reed type check valves at the juncture of the intake manifold with a crankcase chambers of the engine to preclude loss of compression back through the induction system. Furthermore, it is desirable if the induction system has a common portion to provide for a single air filter element for all chambers and also so as to permit the use of a single throttle valve. When the manifold has plural outlets, reed type check valves and a single inlet, however, it is necessary to insure that all of the runners of the manifold have substantially the same length.
It is, therefore, a still further object to this invention to provide an improved induction system for a two cycle, crankcase compression, internal combustion engine having multiple cylinders and embodying a manifold with a single air inlet and runners that have substantially the same length.